fix(FEC-11473): start of dvr window is going back and forth while sta…

…rt over (#165)

shaka is increasing the `seekRange.start` between manifest loadings.
so ignore this update if it's start over.

Solves FEC-11473

karma.conf.js

@@ -34,7 +34,7 @@ module.exports = function (config) {
     client: {
       mocha: {
         reporter: 'html',
-        timeout: 10000
+        timeout: 20000
       }
     }
   };

src/dash-adapter.js

@@ -216,6 +216,9 @@ export default class DashAdapter extends BaseMediaSourceAdapter {
    * @private
    */
   _thumbnailController: ?DashThumbnailController;
+  _isStartOver: boolean = true;
+  _seekRangeStart: number = 0;
+  _startOverTimeout: TimeoutID;
 
   /**
    * Factory method to create media source adapter.
@@ -719,6 +722,7 @@ export default class DashAdapter extends BaseMediaSourceAdapter {
     this._eventManager.listen(this._shaka, ShakaEvent.DRM_SESSION_UPDATE, this._adapterEventsBindings.drmsessionupdate);
     this._eventManager.listen(this._videoElement, EventType.WAITING, this._adapterEventsBindings.waiting);
     this._eventManager.listen(this._videoElement, EventType.PLAYING, this._adapterEventsBindings.playing);
+    this._eventManager.listen(this._videoElement, EventType.LOADED_DATA, () => this._onLoadedData());
     this._eventManager.listenOnce(this._videoElement, EventType.PLAYING, () => {
       this._eventManager.listen(this._shaka, ShakaEvent.BUFFERING, this._adapterEventsBindings.buffering);
     });
@@ -744,6 +748,17 @@ export default class DashAdapter extends BaseMediaSourceAdapter {
     });
   }
 
+  _onLoadedData(): void {
+    const segmentDuration = this.getSegmentDuration();
+    this._seekRangeStart = this._shaka.seekRange().start;
+    this._startOverTimeout = setTimeout(() => {
+      if (this._shaka.seekRange().start - this._seekRangeStart >= segmentDuration) {
+        // in start over the seekRange().start should be permanent
+        this._isStartOver = false;
+      }
+    }, (segmentDuration + 1) * 1000);
+  }
+
   /**
    * Custom parser to retrieve image adaptation sets.
    * @param {ArrayBuffer} manifestBuffer - The array buffer manifest from the response.
@@ -846,6 +861,7 @@ export default class DashAdapter extends BaseMediaSourceAdapter {
     this._thumbnailController = null;
     this._clearStallInterval();
     this._clearVideoUpdateTimer();
+    clearTimeout(this._startOverTimeout);
     if (this._eventManager) {
       this._eventManager.removeAll();
     }
@@ -1300,7 +1316,7 @@ export default class DashAdapter extends BaseMediaSourceAdapter {
    */
   getStartTimeOfDvrWindow(): number {
     if (this.isLive() && this._shaka) {
-      return this._shaka.seekRange().start + this._shaka.getConfiguration().streaming.safeSeekOffset;
+      return (this._isStartOver ? this._seekRangeStart : this._shaka.seekRange().start) + this._shaka.getConfiguration().streaming.safeSeekOffset;
     }
     return 0;
   }

test/src/dash-adapter.spec.js

@@ -1342,9 +1342,8 @@ describe('DashAdapter: getStartTimeOfDvrWindow', () => {
 
   it('should return the start time of Dvr window for live', done => {
     dashInstance = DashAdapter.createAdapter(video, liveSource, config);
-    dashInstance
-      .load()
-      .then(() => {
+    video.addEventListener(EventType.LOADED_DATA, () => {
+      setTimeout(() => {
         try {
           Math.floor(dashInstance.getStartTimeOfDvrWindow()).should.equal(
             Math.floor(dashInstance._shaka.seekRange().start + dashInstance._shaka.getConfiguration().streaming.safeSeekOffset)
@@ -1353,10 +1352,9 @@ describe('DashAdapter: getStartTimeOfDvrWindow', () => {
         } catch (e) {
           done(e);
         }
-      })
-      .catch(e => {
-        done(e);
-      });
+      }, (dashInstance.getSegmentDuration() + 2) * 1000);
+    });
+    dashInstance.load();
   });
 });